A removable tip type rotary tool is known that has (a) a body forming a shaft shape and having a screw hole disposed concentrically with a shaft center O and a fluid supply path disposed in communication with the screw hole, (b) a tip concentrically attached to a leading end portion of the body in a removable manner, rotationally driven around the shaft center O along with the body for predetermined processing, and disposed with a mounting hole penetrating through the shaft center of the tip, and (c) a mounting screw penetrating the mounting hole of the tip and screwed into the screw hole of the body to integrally fix the tip to the body. A removable tip type tap described in Patent Document 1 is an example thereof and fluid is guided to the leading end side of the tip via a fluid introduction path disposed on the shaft center of the mounting screw and is discharged outside.
Although a removable tip type thread forming tap 150 of FIG. 11 has a tip 156 attached in a removable manner via a mounting screw 154 to a body 152 in the same way, a fluid supply path 158 is branched into a Y shape before reaching a screw hole such that fluid is supplied to the tip 156 from the outside. The opposing surfaces of the body 152 and the tip 156 axially opposed to each other have multiplicities of meshing teeth 160 and tooth grooves 162, respectively, disposed alternately and radially as depicted in (b) and meshed with each other so that the surfaces are integrally fixed in a relatively non-rotatable manner.